Corrosion remains a major challenge for the durability of reinforced concrete structures, particularly those exposed to harsh marine environments. This deterioration is primarily driven by chloride ions diffusing through the concrete matrix and accumulating at the steel and concrete interface. While methods have been developed to forecast corrosion damage distributions considering advanced damage states in which corroding sections of reinforcement are electrochemically coupled to passive regions, such models are not capable of resolving complexities of the early stages of corrosion in which localized pitting can progress to widespread corrosion. In this work, we investigate how concrete pore characteristics may potentially impact pit stability using both experimental electrochemical techniques and physics-based modeling. Hemispherical pit geometries are considered to simulate realistic corrosion morphologies, and experiments are conducted in marine environments with and without porous diffusion barriers to establish critical conditions required for pit growth in porous media. Modeling extends these results to simulate pit chemistry evolution in the presence of interfacial gaps, allowing for quantitative comparisons of pit stability between aqueous and concrete-relevant conditions.The results show evidence that the concrete matrix and the conditions of the steel and concrete interface can influence corrosion stability conditions relative to free electrolyte systems.
